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Synthesis and Characterization of C60-Porphyrin Derivatives for Enhanced Photovoltaic Performance through Efficient Charge Generation and Transport

Wang, Chien-Lung
http://rave.ohiolink.edu/etdc/view?acc_num=akron1301353045

Abstract Details

2011, Doctor of Philosophy, University of Akron, Polymer Science.
Although organic bulk-heterojunction photovoltaics has been developed for over 15 years, active material with ideal morphology for efficient solar radiation to electricity conversion has not yet been achieved. The thermally unstable morphology and convoluted charge transport pathway in this system lead to less efficient charge generation and transport. “Double cable polymers” comprised of p-type conjugated polymer backbone and n-type semiconductor side chains has been proposed to form thermally stable phase-separated electron donor (D)/electron acceptor (A) domains on the nanometer scale. However, due to the lack of control over primary chemical structure and secondary physical structure, desired phase structure obtained from this concept is still absent. This dissertation demonstrates two well-defined, thermally stable, supramolecular double cable structures with one p-type porphyrin columnar channel and three n-type C60 side channels formed by monoC60-Por 7 and 13. The helical structure of the column was determined to be a 12944 helix. Deshielding the C60 moiety from the peripheral alkyl chains allows the intercolumnar interaction of C60s. MonoC60-Por 15 thus forms a Colr phase, which has a core porphyrin columnar channel and four peripheral C60 side channels in close contact with the C60 channels in the neighboring columns. The well-defined and oriented bulk material contains a parallel array of hole and electron transport channels that are phase-separated at the molecular level. The structures provide large D/A interface and efficient charge transporting properties, which are highly desired for high photovoltaic performance. This supramolecular approach in the construction of such structures allows further performance optimization through molecular structural modifications to adjust and improve/balance the electronic properties in these hierarchical structures. It holds great promise in meeting all of the essential requirements for photovoltaic applications in a readily processible single molecular system. With two C60 moieties per molecule, trans-diC60-ZnPor (16) formed a thermally stable supramolecular sandwich structure constructed via alternative stacking of Zn (II) porphyrins and C60s. The formation of this stable phase is kinetically slow and requires annealing. Thus, a less ordered metastable phase was observed when directly cooled from the I phase. Compared to the supramolecular double cable structures formed by monoC60-Pors, increase of the number of C60 segments completely changes the phase behavior and phase structure of the C60-Por derivatives. Thus, formation of ordered phases of C60-Por derivatives relies on delicate molecular design and balance among C60-C60, Por-Por and C60-Por interactions.
Stephen Z. D. Cheng, Dr. (Advisor)
Darrell H. Reneker, Dr. (Committee Chair)
Li Jia, Dr. (Committee Member)
Chrys Wesdemiotis, Dr. (Committee Member)
David A. Modarelli, Dr. (Committee Member)
150 p.
Chemistry; Materials Science; Molecular Physics; Physical Chemistry
supramolecular materials; photovoltaics; liquid crystals; fullerenes; porphyrins

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Citations

  • Wang, C.-L. (2011). Synthesis and Characterization of C60-Porphyrin Derivatives for Enhanced Photovoltaic Performance through Efficient Charge Generation and Transport [Doctoral dissertation, University of Akron]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=akron1301353045

    APA Style (7th edition)

  • Wang, Chien-Lung. Synthesis and Characterization of C60-Porphyrin Derivatives for Enhanced Photovoltaic Performance through Efficient Charge Generation and Transport. 2011. University of Akron, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=akron1301353045.

    MLA Style (8th edition)

  • Wang, Chien-Lung. "Synthesis and Characterization of C60-Porphyrin Derivatives for Enhanced Photovoltaic Performance through Efficient Charge Generation and Transport." Doctoral dissertation, University of Akron, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1301353045

    Chicago Manual of Style (17th edition)

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© 2011, all rights reserved.
This open access ETD is published by University of Akron and OhioLINK.